Dimerisation process



United States Patent DIMERISATION PROCESS James Keith Hambliug, Frimley,near Aldershot, and

John Robert Jones, Walton-ou-Thames, Surrey, England, assignors to TheBritish Petroleum Company Limited, London, England, a corporation ofEngland No Drawing. Filed June 20, 1966, Ser. No. 558,588 Claimspriority, application Great Britain, June 21, 1965,

26,100/ 65; Apr. 25, 1966, 17,902/66, 17,904/ 66 Int. Cl. C07c 3/12,3/10 US. Cl. 260-68315 10 Claims ABSTRACT OF THE DISCLOSURE A processfor the production of a product consisting predominantly of lineardimers having an internal double bond is provided, which processcomprises dimersing an alpha mono olefin containing 3 or more carbonatoms per molecule in the presence of a catalyst comprising nickelacetyl acetonate and an activating agent selected from the groupconsisting of aluminium alkyl alkoxides and aluminium trialkyls, themolar ratio of nickel acetyl acetonate to activating agent being in therange 2:1 to 0.1:1 at a temperature in the range 40 to 200 C. under suchconditions of pressure that the reactants are maintained in the liquidor partially condensed phase.

This invention relates to a process for the production of dimers ofalpha-olefins, particularly linear dimers.

Processes for the dimerisation of alpha olefins in the presence ofaluminium alkyls, either as the sole catalytic entity or in combinationwith a minor proportion of an activator, are known.

British patent specification No. 713,081-Ziegler discloses a process forthe polymerisation of ethylene which comprises contacting ethylene at atemperature within the range 60250 C. with an activator selected fromhydrides of aluminium, gallium, indium and beryllium and derivatives ofsuch hydrides in which one or more of the hydrogen atoms are substitutedby hydrocarbon radicals selected from the group consisting of alkylradicals and monovalent aromatic hydrocarbon radicals.

In particular, British patent specification No. 713,081 discloses thepolymerisation of ethylene to butene-l and higher linear alpha-olefinsby contacting ethylene with aluminium triethyl at 200220 C. undersuper-atmospheric pressure.

British patent specification No. 742,642Zieg1er discloses a process forthe dimerisation of a mono-olefin containing more than two carbon atomsin the molecule which comprises heating the mono-olefin at a temperaturewithin the range 60250 C. in the presence of an activator selected fromthe hydrides of beryllium, aluminium, gallium and indium and derivativesof such hydrides in which one or more of the hydrogen atoms aresubstituted by hydrocarbon radicals selected from the group consistingof alyky radicals and mono-valent aromatic hydrocarbon radicals.

In particular British patent specification No. 742,642 discloses thedimerisation of propylene to a product consisting predominantly of2-rnethylpentene-1 by contacting propylene with aluminium triethyl attemperatures in the range l80-240 C. under super-atmospheric pressure.

British patent specification No. 773,536-Ziegler discloses a process forthe catalytic polymerisation of ethylene to form butene, hexene orhigher liquid or solid paraffin-like polymers or mixtures thereof in thepresence of an aluminium trialkyl of general formula ice wherein R R andR represent similar or dissimilar alkyls, in which the aluminum trialkylis activated by nickel, cobalt or platinum.

In particular British patent specification 773,536 discloses thepolymerisation of ethylene to butene-l and higher linear alpha-olefinsby contacting ethylene with aluminium triethyl and a minor proportion ofnickel acetyl acetonate at C. The advantage of the process described inBritish patent specification 773,536 with respect to prior artprocesses, e.g. 713,081, is stated to lie in the fact that it can beeffected at much lower temperatures.

One would therefore expect that the dimerisation of an alpha-olefin, forexample propylene in the presence of a catalyst comprising an activatingagent, for example an aluminium trialkyl and a complex nickel compound,for example nickel acetyl acetonate, would result in the production of aproduct consisting predominantly of a branched chain olefin, for exampleZ-methylpentene-l, and that this process could be eifected at lowertemperatures than those disclosed in British patent specification742,642.

We have surprisingly discovered that dimersing an alpha-olefin in thepresence of a catalyst comprising a relatively large proportion of acomplex organic compound of a metal of Groups I-B or VIII of thePeriodic Table according to Mendeleef and a reducing agent results inthe production of a product which consists predominantly of lineardimers having an internal double bond.

According to the present invention there is provided a process for theproduction of a product consisting predominantly of linear dimers havingan internal double bond which, process comprises dimerising andalpha-olefin in the presence of a catalyst comprising a complex organiccompound of a metal of Group VIII of the Periodic Table according toMendeleef and an activating agent at a temperature in the range 40 to+200 C., under such conditions of pressure that the reactants aremaintained in the liquid or partially condensed phase.

Suitable activating agents are Grignard reagents, metal alkyls and otherorgano metallic compounds.

The preferred complex organic compound is nickel acetyl acetonate.

Preferably the moisture content of the nickel acetyl acetonate isreduced to below 3% by Weight before use. In general, the lower themoisture content the better.

The preferred activating agents are organo aluminum compounds, mostpreferably aluminium alkyl alkoxides.

The preferred aluminium alkyl alkoxide is aluminium didiethyl ethoxide.Aluminum trialkyls, e.g., aluminium triethyl are also suitable.

Aluminium dialkyl alkoxides are preferred because they react gently withthe complex organic compound and catalysts of consistent quality areobtained in successive preparations. Some other activating agents, e.g.,aluminium trialkyls, react more vigorously and render temperaturecontrol of the catalyst preparation reaction more difficult. As aresult, it is more diflicult to obtain catalysts of consistent quality.Nevertheless, useful catalysts are obtained from such agents.

Preferably dimerisation is effected under a pressure in the range 200 to2000 p.s.i.g.

The molar ratio of the Group VIII compound to the activating agent issuitably in the range 2:1 to 0.1 l, preferably in the range l.-0:0.8 to1:2.

Preferably the catalyst is prepared by adding the complex organiccompound of the Group VIII metal and the activating agent to an inertdiluent. Suitable diluents include normally liquid hydrocarbons andhalogenated hydrocarbons. The preferred diluents are aromatic andhalogenated aromatic liquids, e.g., benzene, toluene, xylene andchlorobenzene. The latter act as solvents for both EXAMPLE 1 2.5 g.anhydrous nickel acetyl acetonate were slurried in 50 ml. cyclohexane atC. 2.0 ml. aluminium triethyl were added drop-wise to the mixture whichwas stirred magnetically over a 30 minute period. Admixture was car- 4EXAMPLE 2 2.5 g. anhydrous nickel acetyl acetonate were slurried in 21g. n-heptane at 0 to 5 C. 2.0 ml. aluminum diethyl ethoxide were addeddropwise to the mixture which was stirred magnetically over a 30 minuteperiod. Admixture was carried out in an atmosphere of dry, oxygen free,nitrogen. The total mixture was transferred to a 1 litre stainless steelrocking autoclave which was then pressured with propylene at 600p.s.i.g. and 40 C. After a reaction period of 16 /2 hours, the totalreaction products were collected in traps cooled by solid carbon dioxideand acetone. 70 g. total polymer were obtained. This was found tocontain 83% hexenes. The hexene fraction contained 78% linear hexenesand 8.3% Z-methylpentene-Z.

EXAMPLES 3-5 The procedure of Example 2 was repeated. Reactionconditions and product analyses are set out in the followried out in anatmosphere of dry, oxygen-free, nitrogen. 20 ing Table 1.

TABLE 1 [Polymerisation efiected at 40 C. and 600 p.s.i.]

Addition of Catalyst Reactants AlEtzOEl; cc. Mole ratio ExampleNi(AcAc)z (g.) (as 10%soln) NizAl Solvent Diluent Time Quins.) Temp, C

2. 5 2. 0 1. 0:1. 35 21 g. heptane 05 2. 5 2. 0 1. 0:1. 26 g. toluene 150-5 2. 5 1. 5 1. 0:1. 0 50 g. n-heptane 15 0-5 2. 5 2. 0 1. 0:1. 35 15g. 1./l. benzene/n-heptane- 30 0-5 Hexenes Percent water Reaction TotPercent C Activity g./g./Ni in N1(AcAc)2 time (hours) polymer (g.) inpolymer Percent 110.; Percent 2MP2 (AcAc)2/l1 EXAMPLES 6 AND 7 Example 2was repeated with the exception that the heptane diluent was replaced bya toluene solvent. Reaction conditions and product analyses are set outin the following Table 2.

TABLE 2 [Polymerisation efiected at 40C. and 600 p.s.i.]

Addition 0! Catalyst Reactants AlEtaOEt cc. Mole ratio ExampleNiAcAc(g.) (as 10% soln.) N izAl Solvent diluent Time (mins) Temp. C.

6 2. 5 1. 5 1. 0:1. 0 26 g. toluene 15 0-5 7 2. 5 1. 5 1. 011.0 g.toluene 15 0-5 Hexenes Percent water Reaction Total Percent C Activityg./g.Nl Example 111 Ni(AcAe)2 time (hours) polymer (g.) in polymerPercent n05 Percent 2MP2 (AcAc) 2/ h 114 g. of a residual liquid wereobtained. This was found to contain 26 g. solvent cyclohexane, 71 g.hexenes and 17 g. higher polymers. The hexene fraction contained 74%linear hexenes as indicated in the following table:

2-methylpentene-2 12.0

2-methylpentene-l 6.5 2,3-dimethylbutene-1 1.0 2,3-dimethylbutene-2 0.5

What we claim is:

1. A process for the production of a product consisting predominantly oflinear dimers having an internal double bond which process comprisesdimerising an alpha mono olefin containing 3 to 6 carbon atoms permolecule in the presence of a catalyst comprising nickel acetylacetonate and an activating agent selected from the group consisting ofaluminum alkyl alkoxides and aluminum trialkyls, the molar ratio ofnickel acetyl acetonate to activating agent being in the range 2:1 to0.1 :1 at a temperature in the range -40 to 200 C., under suchconditions of pressure that the reactants are maintained in the liquidor partially condensed phase.

2. A process according to claim 1 wherein the activating agent is analuminium alkyl alkoxide.

3. A process according to claim 2 wherein the activating agent isaluminium diethyl ethoxide.

4. A process according to claim 1 wherein the activating agent is analuminium trialkyl.

5 6 5. A process according to claim 4 wherein the alumini- 10. A processaccording to claim 1 wherein the olefin is um tn'alkyl is aluminiumtriethyl. propylene.

6. A process according to claim 1 wherein the molar ratio of the nickelacetyl acetonate to the activating agent References Cited is in therange 1.0:0.8 to 1:2.

7 A t 1 1 h t l t 5 UNITED STATES PATENTS process accor mg 0 c mm Werein ca ays V preparation is effected in the presence of an inertdiluent. f r 1 260 66 8. A process according to claim 7 wherein thediluent 3321546 5/1967 i et a is an aromatic or halogenated aromaticcompound. Oes a 9. A process according to claim 8 wherein the diluent 103364278 V1968 Reusser' is benzene, toluene or Xylene. PAUL M. COUGHLAN,111., Primary Examiner fgz gy UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent No. 3,483,268 Dated December 9. 1959 Inveutor(a) JamesKeith Hambling and John Robert Jones It is certified that error appearsin the above-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 1, line 57 "alyky" should read --alkyl--;

Column 4, Table I, under the heading "Solvent Diluent" "21 g. heptane"should read --Zl go n-heptane--.

SI'GN ED AND SEALED MAY 1 2 1970 QSEAL) Attest:

M. Fletcher, Ire E. Anesting Officer mmissioner of p

